I was reading my Oct 68 Motor Trend and noticed that their article on the 69 Chevy's showed pictures of the 69Z with a cowl induction hood. The article refered to the hood as a "proterbant plenum chamber" along the top of the hood.

My understanding of magazines, esp back then is that the pics and articles were written weeks in advance.

If the ZL1 ducted hood was already talked about in the Oct 68 Motor Trend, why did it take until Dec 68 to apear as an option?

The hood on the car in the article was an Engineering prototype/pre-production part, made from temporary tooling; an October '68 cover date meant the car was probably driven in June or July '68, before '69 production started.